De-icing slippery winter roads is a vital public safety measures in cold-weather climates. However, the annual cycle of salting streets only to have the mineral seep into the blacktop and rot it from the inside wreaks havoc on transportation infrastructure throughout the U.S. and around the world. This little bot helps fix that.

The problem is especially acute in Switzerland, where more than 3,500 concrete-reinforced bridges and cantonal roads whisk travelers between the nation's numerous mountain hamlets and across its plentiful scenic valleys. The rebar rods submerged in reinforced concrete are especially susceptible to road-salt-induced corrosion and often show little sign of external damage until they're nearly destroyed. And the more damaged a road section is when crews actually discover the problem, the more expensive it is to repair or replace it—which is why early detection is key. Of course, lifting a full-grown inspector up to check the undersides of thousands of overpasses is a difficult, time- and labor-intensive venture. But that's where the C2D2 robotic bridge inspector comes in.

Designed by a consortium of researchers from the Institute for Building Materials and the Autonomous Systems Lab at ETH Zurich and patented in 2012, the C2D2 is built to go where humans can't and detect hidden rebar corrosion as soon as it begins to form.

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"The students in one of our focus projects developed a robot four years ago that can move not only on the ground, but also along walls and ceilings," Roland Siegwart, professor at the Institute of Robotics and Intelligent Systems and Vice President Research and Corporate Relations at ETH Zurich, explained in a press statement. "This made it ideal for our project."

The C2D2 was originally designed to act as a g0-anywhere camera for film shoots. "The robot was originally called Paraswift and was developed with a view to being used by Disney. When a camera is screwed on to the robot, it can easily film a room from all perspectives," Siegwart continued. It is able to stick to walls and ceilings thanks to a movable, active-suction cup system wherein a propeller mounted to the bottom of the vehicle generates the sucking force, while its four wheels propel the robot forward and back. The researchers also replaced the C2D2's original onboard cinema camera with one designed more for navigation and obstacle avoidance. The team also installed a pink ball around the nav-cam so that cameras and crews on the ground can spot it more easily. The team also added a corrosion-identification system—essentially an electrode that measures the electrical potential differences in various parts of the structure. The bigger the potential difference is, the worse the hidden corrosion is.

The robot currently must be controlled directly by an operator either via remote control or terminal uplink, though the team hopes to incorporate a self-steering measure in the robot's next iteration, as well as analytical software to automatically sense the presence of corrosion without the need for human intervention. The team hopes to have that version ready by the middle of next year.

The project, which is being funded by Switzerland's Federal Roads Office, must pass a few more rounds of testing, however, before it is widely implemented—including how well its upcoming self-navigation system performs as well as its ability to climb vertical surfaces. Though, as you can see above, the robo-inspector has little issue with being inverted. [ETH Zurich]